The present invention relates to a method for manufacturing a stator for use in a rotating machine such as an inner rotor type electric motor having a cylindrical stator.
A conventional stator for use in an inner rotor type electric motor is manufactured by a so-called inserting method. According to this method, a coil wound around a frame is inserted into a slot between adjacent teeth of a plurality of teeth projecting from the inner circumferential side of a cylindrical stator core.
The present applicant has proposed a stator core, comprising a core main body having a plurality of teeth projecting from the outer circumferential side thereof and a ring member fitted on the outer circumferential portion of the teeth, disclosed in Japanese Laid-Open Patent Publication No. 58-33945. According to this stator core, a coil is directly wound by a flyer on the teeth positioned on the outer circumferential side of the core main body.
According to the conventional inserting method, a coil is shaped after it is wound, the coil is inserted into a slot through a slit positioned between edge portions of adjacent teeth, portions of the coil projecting from both edges of the stator core are shaped to fix them to a predetermined member, and then the wind start and terminating portions of the coil, i.e. the outgoing lines, are fixed to fixing members. As such, the method requires a lot of steps and its manufacturing process is complicated, so that its productivity is low and it is very difficult to automate the manufacturing process.
According to the method disclosed in Japanese Laid-Open Patent Publication No. 58-33945, since the coil is directly wound around the core main body, it is unnecessary to insertion the coil and perform subsequent operations after the insert of the coil. The manufacturing process can be simplified to a great extent; however, the method still requires time and labor to fix the outgoing lines of the coil to fixing members. However it is difficult to automate the manufacturing process.
It is difficult to know the number of turns (hereinafter referred to as the space factor) of the coil which can be wound in a slot formed between teeth and in addition, the space between the outer circumferential portion of the coil and the projection positioned on the edge of the tooth is small, so that it is difficult to insert a wedge therebetween.